Injectors are devices that expel fluid, such as contrasting media, from a syringe and through a tube into a patient. The injectors are provided with an injector unit, usually adjustably fixed to a stand or support, having a drive that couples to the plunger of the syringe to drive it forward to expel fluid into the tube, or that may be driven rearward to draw fluid into the syringe to fill it. Usually the syringe is a disposable replacement type.
In the injection phase where the plunger is driven forward, pressures are developed in the syringe that range from, for example, 25 psi for some applications to over 1000 to 1200 psi for other applications. Syringes that contain fluid under the higher range of pressures are expensive and therefore can be impractical where the syringes are disposable. Thus, many injectors for high pressure applications have been provided with pressure jackets that are fixed to the injector units and into which the syringes are inserted. The pressure jackets contact the outer surfaces of the syringe to restrain the walls of the syringe against the internal pressures. Other syringes for lower pressure use do not have a pressure jacket.
The injectors described in U.S. Pat. No. 5,300,031; U.S. Pat. No. 5,451,211; and U.S. Pat. No. 5,658,261 use a syringe that must be oriented to a single position to orient the nozzle and tubing connector when the syringe is loaded in the injector. This required orientation hinders rapid attachment and replacement of the syringe. In addition, although the Luer connection, syringe/tubing connection, described in the above patents may be adequate for injector applications that use low pressures, leaks often occur when high pressure applications are used. Power injectors require the connection of the Luer lock system to be effective for pressures up to 1,200 p.s.i. Some users have attempted to remedy the leak problem by tightening the connection as much as possible. Over-tightened Luer connectors sometimes crack which compromises the seal. Another problem is that sometimes the connection sticks and the Luer lock cannot be disassembled.
Hence, there has been a need to more quickly load and unload disposable replacement syringes in injectors, and for injectors and replacement syringes that can accommodate a more efficient process of syringe replacement. There is also a need for a fluid tubing delivery system, such as a Luer lock system, that does not leak when used with power injectors.